فهرست مطالب

  • Volume:2 Issue:8, 2013
  • تاریخ انتشار: 1392/08/10
  • تعداد عناوین: 3
|
  • Anoop Yadav, Renuka Gupta, Vinod Kumar Garg Page 1
    Background
    Vermicomposting is a biological process which may be a future technology for the management of animal excreta. This study was undertaken to produce vermicompost from cow dung and biogas plant slurry under field conditions. To achieve the objectives، two vermicomposting units containing cow dung (CD) and biogas plant slurry (BPS) were established، inoculated with Eisenia fetida species of earthworm and allowed to be vermicomposted for 3? months.
    Results
    After 3? months، the vermicompost was harvested and characterized. The results showed that the vermicompost had lower pH، total organic carbon (TOC)، organic matter (OM) and carbon/nitrogen ratio (C/N ratio) but higher electrical conductivity (EC)، nitrogen، phosphorous and potassium (NPK) content than the raw substrate. The heavy metal content in vermicomposts was higher than raw substrates.
    Conclusions
    During vermicomposting، the CD and BPS were converted into a homogeneous، odourless and stabilized humus-like material. This experiment demonstrates that vermicomposting is an environmentally sustainable method for the management of animal excreta.
    Keywords: Cattle dung, Vermicompost, Eisenia fetida, Heavy metals, C, N ratio
  • Sayyed Mohammad Javad Mirzaei, Manouchehr Heidarpour, Sayyed Hassan Tabatabaei, Payam Najafi, Seyyed Ebrahim Hashemi Page 15
    Introduction
    Soil hazardous heavy metal pollution is increasingly a decisive problem all over the world. One of the problems associated with organic fertilizer factories is the discharge of leachate containing solid wastes. The leachate percolates through the soil and where there is no proper leachate filtration, this discharge could be potentially a primary pollution source of soil and water resources. Iran has limited water resources and oppositely large number of unused lands. Therefore, properly managed land treatment may be a suitable solution for the filtration of leachate before it enters the environment or is reused as irrigation water. To investigate the potentiality of soil-zeolite in the immobilization of heavy metals and prevention of groundwater contamination, a lysimeter study was performed with two types of soil texture (clay loamy and loamy sand) and two levels of zeolite and a blank (0, 5, and 10%).
    Results
    The results showed that soil with a clay loamy texture can adsorb heavy metals such as Cr3+, Pb2+, Ni2+, and Cd2+ from influent leachate stronger than soil with loamy sand texture. Application of zeolite had a significant effect (p < 0.05) on Pb2+, Ni2+, and Cr3+ concentration in the effluent. Increasing applied zeolite, reduced the concentrations of these heavy metals in the effluent. Furthermore, application of zeolite and irrigation with leachate decreased the bulk density, hydraulic conductivity, and infiltration of the soil in all treatments.
    Conclusion
    Briefly, this research indicated that land treatment is a good way to reduce leachate electrical conductivity (EC) and elimination of leachate heavy metals.
    Keywords: Heavy metal, Infiltration, Leachate, Saturated hydraulic conductivity, Zeolite
  • Priyankari Bhattacharya, Sourja Ghosh, Aniruddha Mukhopadhyay Page 30
    Background
    The present study was undertaken to evaluate the efficiency of combined technology involving ceramic microfiltration and biosorbent for the treatment of tannery effluent from different streams, viz. composite effluent, effluent from primary clarifier and secondary clarifier. The membranes were prepared from a cost-effective composition of alumina and clay.
    Results
    The effluents had high organic loading of 12,895, 3,890 and 410 mg/L, respectively, in terms of chemical oxygen demand (COD). Apart from these, the effluents consisted of toxic heavy metals, turbidity, biochemical oxygen demand (BOD), etc. It was observed that COD reduction was about 96.5% for effluent 1, 96.6% for effluent 2 and 96.9% for effluent 3. Considerable reduction in suspended solids, total nitrogen, and total organic carbon was obtained. Turbidity for all three types of effluent was below 1 NTU. The average flux value for effluents 1, 2 and 3 was about 13, 19 and 24 L/m2/h (LMH), respectively. Response of the antioxidative defences of Euphorbia hirta was observed which resulted in considerable decrease in the activity of peroxidase, superoxide dismutase and catalase.
    Conclusions
    The treatment resulted in the reduction of toxicity thereby restoring normal activity when compared to control values. Changes in various biochemical parameters like protein, amino acid, carbohydrate, DNA, RNA and chlorophyll content were observed.
    Keywords: Tannery effluent, Biosorbent, Ceramic membrane, Microfiltration, Reuse, Euphorbia sp